triiodothyronine--reverse and Atrial-Fibrillation

To fully investigate the thyroid hormonal function in patients with the most common arrhythmia - atrial fibrillation.. 120 patients (aged 55-85 yrs) with symptoms of congestive heart failure exacerbation and no other concomitant disorders (inclusion criteria: normal cardiac troponin T at admission and 12 hours after, normal renal, hepatic and respiratory function; exclusion criteria: inflammatory state, history of myocardial infarction). Depending on the presence of permanent atrial fibrillation (PAF), patients were divided into two groups: PAF (34 females, 26 males) and regular sinus heart rhythm (43 females, 17 males), the groups did not differ in terms of heart rate, blood pressure, presence of overt/subclinical thyroid dysfunction, and medical therapy used. In all subjects thyroid stimulating hormone, free thyroxine, free triiodothyronine, reverse triiodothyronine were measured; echocardiography was performed.. PAF group showed higher FT4 and rT3 (1.41 vs. 1.27 ng/dl, p=0.0007; 0.61 vs. 0.32 ng/ml, p<0.0001, respectively). With ROC curve analysis the biochemical thyroid related factor of the highest prognostic value for PAF occurrence (with the highest sensitivity and specificity: 77% and 72%, respectively) was rT3 with the cut-off of above 0.3 ng/ml. Also, a positive correlation between rT3 levels and left ventricular posterior wall diameter was observed (Spearman's correlation coefficient 0.33, p=0.0093).. PAF is another condition where an increase in rT3 is observed. rT3 concentration above 0.3 ng/ml may be a novel biochemical sign associated with the presence of PAF in patients with chronic heart failure.

Topics: Aged; Aged, 80 and over; Atrial Fibrillation; Case-Control Studies; Cohort Studies; Female; Heart Failure; Humans; Hyperthyroidism; Hypothyroidism; Male; Middle Aged; ROC Curve; Thyroid Function Tests; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Amiodarone, a widely used iodine-containing antiarrhythmic drug, has been shown to divert the peripheral metabolism of T4 towards rT3 than T3. In this prospective study we correlated the concentration of the peripheral thyroid hormones in serum with that of amiodarone. Fifteen euthyroid volunteers were studied, 5 men and 10 women, with a mean age of 64.2 yr, who suffered from various cardiac arrhythmias (atrial fibrillation or multiple ventricular extrasystoles). Serum amiodarone, T4, T3, rT3 and TSH were determined before and 3, 7, and 14 days after the administration of 400-600 mg amiodarone/day. There was a small increase in serum T4 and a suggestive decrease in serum T3. The increase in serum rT3 was significant, with p less than 0.05 for 3 days, p less than 0.01 for 7 days and p less than 0.005 for 14 days. There was a significant correlation between the level of serum amiodarone and the rise in serum rT3 (r = 0.385, p less than 0.05). The rise in rT3 is the main thyroid abnormality after amiodarone administration and may be used as a rough index of the serum concentration of this drug.

Topics: Aged; Amiodarone; Atrial Fibrillation; Benzofurans; Female; Humans; Male; Middle Aged; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse; Ventricular Fibrillation